Merge branch 'sparse-coef'

Conflicts:
	doc/whats_new.rst
COSMIT callable instead of hasattr __call__
BUG update graph_laplacian to upstream SciPy version

Fixes several bugs and I hope #1698 as well.
DOC rm failing doctest on graph_laplacian
DOC fix text vectorizer docs and add NLTK example

The narrative docs did not correctly describe the working of a custom
analyzer, which will actually skip the built-in preprocessing and
tokenization.
DOC fix broken doctests for feature_extraction.text

This time, I actually did run the doctests, but they succeeded
because I have NLTK installed.
StratifiedKFold: remove pointless copy of labels
DOC add random_state parameter to docs of LogisticRegression and LinearSVC
TST/FIX set random_state in logistic regression tests
TST/FIX always use "almost equal" for floats.
ENH CountVectorizer using arrays instead of lists
BUG restore empty vocabulary exc in CountVectorizer
ENH prevent copying of indices in CountVectorizer

... and values as well, if possible.
DOC credit @ephes
Merge pull request #1713 from larsmans/vectorizer-memory-use

ENH CounterVectorizer using arrays instead of lists
FIX MinMaxScaler bug.
COSMIT use callable instead of hasattr
Merge pull request #1727 from amueller/min_max_scaler_fix

FIX MinMaxScaler bug
FIX : fix kfold balance due to int rounding
FIX : test due to KFold change